The present disclosure generally relates to a process and a production device for producing at least one analytical device and to an analytical device producible by the process, and in particular, to the field of manufacturing analytical devices such as test elements for detecting at least one analyte in a sample, such as for manufacturing test elements for detecting at least one analyte in a sample of a body fluid.
One or more analytes present in a body fluid may be detected, such as one or more analytes which may participate in a metabolism of a human or animal, such as, one or more analytes such as glucose, lactate, triglycerides or cholesterols. The body fluid may be an arbitrary body fluid, such as blood, interstitial fluid, ocular fluid, tear fluid, saliva or urine. Other embodiments are feasible. The analytical device specifically may be applicable in the field of professional monitoring or in the field of home monitoring of at least one health state of a person, such as in the field of diabetes care. Other uses are feasible.
In the field of medical technology, specifically in the field of medical analytics, a large number of analytical devices are known. In the following, without wishing to restrict the present disclosure to specific embodiments, the present disclosure is explained in view of the production of test elements for detecting at least one analyte in a sample, such as in a sample of a body fluid. However, other types of analytical devices having at least one capillary element are feasible.
Analytical devices, such as test elements, often are produced by using continuous processes, using cutting techniques, wherein the analytical devices are cut from one or more continuous webs or tapes. Cutting processes are well known in the art such as, as an example, an apparatus for cutting and assembling batches of diagnostic strips and for transferring predetermined numbers of strips into bottles or the like. The apparatus has a rotary knife set which slits cards into strips and directs alternate ones of the strips into slots on one side of a carrier and directs the others of the strips into slots at the opposite side of the carrier. The strips are delivered to collection chambers for transfer to vials, by relative movement of the carrier and collection chambers.
One major technical challenge in the production of analytical devices, such as in the production of test strips, is the mass-production of fluidic structures. Thus, as an example, many analytical devices comprise one or more capillary elements, for example for transporting a sample of a fluid from an application position to an analysis position within the analytical device. For providing capillary elements in a continuous process, a process for the production of analytical devices is known. The analytical devices include analytical test elements with a capillary-active zone for examining fluid samples. In the process, a carrier layer is prepared, a spacer layer is laminated onto the carrier layer, a contour is punched, cut or stamped through the spacer layer laminated onto the carrier layer which determines the shape of the capillary-active zone. Those parts of the spacer layer which are not required to form the capillary-active zone are removed from the carrier layer, and a cover layer is applied to the spacer layer to result in a capillary-active zone.
Despite the advantages, a large number of technical challenges remain. Thus, the process is limited with regard to the width of the capillary elements. Thus, specifically, thin capillary elements, having a width of below 2 mm, remain a challenge, depending on the strength or thickness of the spacer layer. Thus, often, double-sided adhesive tapes are used. With increasing thickness of the adhesive tapes, however, the minimum width of the capillary element producible by the cutting process increases. This is due to the fact that a rotary cutting tool having at least two opposing blades is used, in order to cut out those parts of the spacer layer which are not required for shaping the capillary-active zone, i.e. the inner part of the capillary elements. This cutting tool, however, in most cases fails to provide sufficient space for pushing aside the unwanted inner part of the capillary element. As a result, specifically when cutting the capillary element on the carrier layer, the capillary activity may be reduced, and residuals of an adhesive within the capillary channel may remain. Further, the cutting tool may even be damaged or destroyed during the cutting process, since the cutting blades or edges in many cases are unable to stand the pressure of the material pushed aside during the cutting process.
A further technical challenge involved in known processes for continuous manufacturing of analytical devices resides in the accuracy of positioning. Thus, specifically when manufacturing a capillary element for application onto a pre-manufactured carrier having one or more structures such as having one or more electrodes already manufactured by printing or laser ablation techniques, rotary cutting tools and endless cutting processes often fail to provide the possibility of compensating for positioning errors. Since the rotary cutting tools provide a fixed surface ratio, the system often is not capable to compensate for continuous changes. Thus, known devices and processes often are unable to compensate for abrupt or continuous changes of process parameters. Consequently, known processes lead to a reduced yield which, mainly, is due to the endless rotary cutting tool which is in continuous engagement with the layer to be cut.
A further disadvantage resides in the fact that the divisor, i.e. the ratio of the capillary width and the distance between neighboring capillaries, remains constant in the process. Consequently, in case the rotary cutting tool is controlled, the width and the position of both the capillary and the non-capillary part of the analytical device are changed simultaneously, thereby keeping the ratio of these two dimensions unchanged. Consequently, manufacturing a capillary element having a constant capillary width, with a varying divisor, is not feasible by known processes.
Therefore, this is a need for a process and a production device for the production of at least one analytical device such as at least one test element that is suited for mass-manufacturing in a continuous process of test elements such as test strips that have one or more capillary elements manufactured with a low width of the capillary elements, such as a width of less than 2 mm or even less than 1.5 mm with a variable divisor and a high-precision control of the width of the capillary elements and the divisor.